The acpica branch is based on 2.6.25-rc9. Below is a dmesg diff of an HP nx6325 booting that baseline vs. booting the acpica branch. Two things jump out: 1. ACPI: Expecting a [Reference] package element, found type 14 2. memory coorruption: slab error in verify_redzone_free(): cache `size-1024': memory outside object was overwritten -Len 1c1 < Linux version 2.6.25-rc9 (lenb@t61) (gcc version 4.1.2 20070925 (Red Hat 4.1.2-33)) #50 SMP Fri Apr 11 22:46:39 EDT 2008 --- > Linux version 2.6.25-rc9-00073-g8b56e6a (lenb@t61) (gcc version 4.1.2 20070925 (Red Hat 4.1.2-33)) #33 SMP Sat Apr 12 00:07:51 EDT 2008 40c40 < early res: 2 [200000-8d9707] TEXT DATA BSS --- > early res: 2 [200000-8d9747] TEXT DATA BSS 95a96 > spurious 8259A interrupt: IRQ7. 102c103 < Memory: 442500k/458560k available (3629k kernel code, 15672k reserved, 2023k data, 364k init) --- > Memory: 442500k/458560k available (3632k kernel code, 15672k reserved, 2020k data, 364k init) 104c105 < Calibrating delay using timer specific routine.. 3194.17 BogoMIPS (lpj=1597086) --- > Calibrating delay using timer specific routine.. 3194.25 BogoMIPS (lpj=1597129) 113c114 < ACPI: Core revision 20070126 --- > ACPI: Core revision 20080321 126c127 < Calibrating delay using timer specific routine.. 3191.63 BogoMIPS (lpj=1595818) --- > Calibrating delay using timer specific routine.. 3191.59 BogoMIPS (lpj=1595798) 154,155c155,156 < Completing Region/Field/Buffer/Package initialization:................................................................................................................................................................ < Initialized 29/33 Regions 0/0 Fields 63/64 Buffers 68/78 Packages (1172 nodes) --- > Completing Region/Field/Buffer/Package initialization:............................................................................................................................................................... > Initialized 29/33 Regions 0/0 Fields 63/64 Buffers 67/78 Packages (1172 nodes) 160a162,168 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 228d235 < PCI: Bridge: 0000:00:05.0 232a240 > PCI: Bridge: 0000:00:05.0 381c389 < usb usb1: Manufacturer: Linux 2.6.25-rc9 ehci_hcd --- > usb usb1: Manufacturer: Linux 2.6.25-rc9-00073-g8b56e6a ehci_hcd 394c402 < usb usb2: Manufacturer: Linux 2.6.25-rc9 ohci_hcd --- > usb usb2: Manufacturer: Linux 2.6.25-rc9-00073-g8b56e6a ohci_hcd 406c414 < usb usb3: Manufacturer: Linux 2.6.25-rc9 ohci_hcd --- > usb usb3: Manufacturer: Linux 2.6.25-rc9-00073-g8b56e6a ohci_hcd 448a457,463 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: LNXTHERM:01 is registered as thermal_zone0 > ACPI: Thermal Zone [TZ1] (67 C) > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: LNXTHERM:02 is registered as thermal_zone1 > ACPI: Thermal Zone [TZ2] (54 C) 452d466 < ACPI: AC Adapter [C1BD] (on-line) 459a474,477 > ACPI: AC Adapter [C1BD] (on-line) > ACPI: Expecting a [Reference] package element, found type 14 > ACPI: LNXTHERM:03 is registered as thermal_zone2 > ACPI: Thermal Zone [TZ3] (29 C) 461a480,487 > ACPI: PNP0C0B:00 is registered as cooling_device2 > ACPI: Fan [C34F] (off) > ACPI: PNP0C0B:01 is registered as cooling_device3 > ACPI: Fan [C350] (off) > ACPI: PNP0C0B:02 is registered as cooling_device4 > ACPI: Fan [C351] (off) > ACPI: PNP0C0B:03 is registered as cooling_device5 > ACPI: Fan [C352] (off) 471a498 > ACPI: WMI: Mapper loaded 481c508 < power_supply C1BF: prop VOLTAGE_NOW=12617000 --- > power_supply C1BF: prop VOLTAGE_NOW=12616000 490,507d516 < ACPI: WMI: Mapper loaded < ACPI: LNXTHERM:01 is registered as thermal_zone0 < ACPI: Thermal Zone [TZ1] (54 C) < ACPI: LNXTHERM:02 is registered as thermal_zone1 < ACPI: Thermal Zone [TZ2] (46 C) < ACPI: LNXTHERM:03 is registered as thermal_zone2 < ACPI: Thermal Zone [TZ3] (28 C) < ACPI: Transitioning device [C34F] to D3 < ACPI: PNP0C0B:00 is registered as cooling_device2 < ACPI: Fan [C34F] (off) < ACPI: Transitioning device [C350] to D3 < ACPI: PNP0C0B:01 is registered as cooling_device3 < ACPI: Fan [C350] (off) < ACPI: Transitioning device [C351] to D3 < ACPI: PNP0C0B:02 is registered as cooling_device4 < ACPI: Fan [C351] (off) < ACPI: PNP0C0B:03 is registered as cooling_device5 < ACPI: Fan [C352] (on) 524c533 < Clocksource tsc unstable (delta = -245722066 ns) --- > Clocksource tsc unstable (delta = -249928054 ns) 527a537,600 > ACPI: PCI Interrupt 0000:01:05.0[A] -> GSI 17 (level, low) -> IRQ 17 > slab error in verify_redzone_free(): cache `size-1024': memory outside object was overwritten > Pid: 96, comm: kacpi_notify Not tainted 2.6.25-rc9-00073-g8b56e6a #33 > > Call Trace: > [] __slab_error+0x24/0x26 > [] cache_free_debugcheck+0x136/0x207 > [] ? acpi_ev_asynch_enable_gpe+0x2b/0x2f > [] kfree+0x9c/0x216 > [] ? acpi_os_execute_deferred+0x0/0x39 > [] acpi_ev_asynch_enable_gpe+0x2b/0x2f > [] acpi_os_execute_deferred+0x2c/0x39 > [] run_workqueue+0x7d/0x106 > [] worker_thread+0xd8/0xe5 > [] ? autoremove_wake_function+0x0/0x38 > [] ? worker_thread+0x0/0xe5 > [] kthread+0x49/0x79 > [] child_rip+0xa/0x12 > [] ? kthread+0x0/0x79 > [] ? child_rip+0x0/0x12 > > ffff81001b028e70: redzone 1:0x800, redzone 2:0x5a5a5a5a5a5a5a5a. > ------------[ cut here ]------------ > kernel BUG at mm/slab.c:2906! > invalid opcode: 0000 [1] SMP > CPU 0 > Modules linked in: powernow_k8 pcmcia snd_hda_intel snd_seq_device snd_pcm_oss snd_mixer_oss snd_pcm snd_timer yenta_socket rsrc_nonstatic snd_page_alloc wmi battery fan video backlight ac thermal > Pid: 96, comm: kacpi_notify Not tainted 2.6.25-rc9-00073-g8b56e6a #33 > RIP: 0010:[] [] cache_free_debugcheck+0x1d0/0x207 > RSP: 0018:ffff81001b037df0 EFLAGS: 00010016 > RAX: ffff81001b028d98 RBX: ffff81001b804ac0 RCX: ffff81001b028150 > RDX: 0000000000000003 RSI: ffff81001b028e70 RDI: ffff81001b804ac0 > RBP: ffff81001b037e20 R08: 09f911029d74e35b R09: 00000000ffffff20 > R10: 0000000000000010 R11: 0000000000000000 R12: 0000000000000800 > R13: ffff81001b028e70 R14: 5a5a5a5a5a5a5a5a R15: ffff81001b028100 > FS: 00000000409b4950(0000) GS:ffffffff80786000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > CR2: 00000030ed8c6d80 CR3: 0000000019c38000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process kacpi_notify (pid: 96, threadinfo ffff81001b036000, task ffff81001bb06740) > Stack: ffffffff8037f2bc ffff81001b80b5e8 ffff81001b804ac0 ffff81001b028e78 > ffffffff807f3bc0 0000000000000282 ffff81001b037e70 ffffffff80281afb > ffffffff807f3bc0 0000000000008025 ffff81001b028e78 ffff81001b028e78 > Call Trace: > [] ? acpi_ev_asynch_enable_gpe+0x2b/0x2f > [] kfree+0x9c/0x216 > [] ? acpi_os_execute_deferred+0x0/0x39 > [] acpi_ev_asynch_enable_gpe+0x2b/0x2f > [] acpi_os_execute_deferred+0x2c/0x39 > [] run_workqueue+0x7d/0x106 > [] worker_thread+0xd8/0xe5 > [] ? autoremove_wake_function+0x0/0x38 > [] ? worker_thread+0x0/0xe5 > [] kthread+0x49/0x79 > [] child_rip+0xa/0x12 > [] ? kthread+0x0/0x79 > [] ? child_rip+0x0/0x12 > > > Code: 29 c8 48 0f af c2 48 89 c2 48 c1 ea 20 3b 93 18 01 00 00 72 04 0f 0b eb fe 89 d0 0f af 83 0c 01 00 00 48 8d 04 01 49 39 c5 74 04 <0f> 0b eb fe 89 d0 41 c7 44 87 30 fe ff ff ff f6 83 15 01 00 00 > RIP [] cache_free_debugcheck+0x1d0/0x207 > RSP > ---[ end trace b34da6ee0b4cc39e ]---